Most of it is in cells controlled by hormones. Rest of body water is in plasma, mucous, bones, and fluid in eyes (among other places) Comes from 3 places: what we drink, water in food we eat, breakdown of food in body. Loss most water is lost through our skin through sweat: sweating evaporates and cools us down. Functions: solvent digestion, lubricant, chemical reactions, regulation of body temperature, structure/shape (of cells) Thirst is an adequate guide in healthy adults, not for. Amounts: fruits and vegetables: 75-96% water, alcohol and caffeine have none, there is no dietary recommendation for water. Dehydration: mood swings, nausea, tingling, headaches, lack of awareness, death. When working out: plain, cool water, fluids with less than 10% sugar. Intoxication: you can have too much, this is rare. Electrolytes: conduct an electric current, have positive and negative charge.